V i t a l W e l l E l e c t r o n i c s P t e L t d
w w w . v i t a l - w e l l . c o m
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CHAPTER IV TRANSPARENT SECURED MODE
In order to confirm the good quality of transmitted data frames and to avoid data
loss, data frame control between radio modems are added to the transparent
mode, so that each data transfer is verified.
IV.1 Operation
Transparent secured mode
’
s purpose is to offer an optimal radio link quality and
to provide transparent mode with the necessary security in case frame control
would not be included within the user
’
s application software. The risk of data loss
is therefore much weaker. Moreover, a flow control, Xon/Xoff can be enabling to
be performed on the serial link in order to warn the user that the data buffer is
saturating.
The receiving unit analyses this data frame and checks its consistency, When the
data frame is received correctly, the receiver transmits an Acknowledgement
back to the transmitter, and delivers the received data frame to its serial link.
In case the reception is not satisfying, no acknowledgement is received by the
transmitter. The transmitter then repeats the data frame transmission after a
random delay. The number of iterations can be configured via S126 register.
Transparent secured mode shall be operated for point-to-point
communications only.
At serial port level, the statements of whether the data frame has been
transmitted or not can be asserted to the user by enable the bit in S128 register.
IV.2 Examples - Configuration with AT commands
User
+++
// Switch to Configuration mode
Modem
>
User
ATS120=192.168<CR>
// Set network ID to 192.168
Modem
>
User
ATS123=120<CR>
// set cluster id to 120
Modem
>
User
ATS124=1<CR>
// Transparent Secure mode
Modem
>
User
ATO<CR>
// Switch to operating mode
Modem
Good Bye!
